About 200 million shares of locked-up shares were
released on October 29 and shares of the social networking site fell 3.4
percent to $21.12 that day and have further plunged to $19.15 since then.

However the market is dreading Wednesday's expiry of
locked-in shares since it is the largest number of shares that will become
available since the company went public in May.

It will also mark the day when Chief Executive and
founder Mark Zuckerberg will become eligible to sell about 504 million of his
shares. But Zuckerberg has already said before in a regulatory filing that he
would not be selling his shares, as a mark confidence in the company.

However it remains to be seen whether any of the top
executives in the company will be following his example, such as Chief
Operating officer Sheryl Sandberg and Chief Financial Officer David Ebersman.

The next expiration date is December 14, when more
than 155.9 million shares may free up. This is when stockholders who sold into
the IPO -- including big names like early backers Peter Thiel and Mark Pincus
and co-founder Dustin Moskovitz -- are free to sell their stock.

After December, the next date to look for is May 18,
when more than 47.3 million shares can be sold. These shares include those held
by investors like Mail.ru Group Limited and DST Global Limited.